Recording on DVDs (Digital Versatile Discs) is performed according the DVD video recording (DVD-VR) standard or the DVD-video standard. The DVD-VR standard is used for real-time recording of contents. On the other hand, contents recorded according to the DVD-video standard can be played back by DVD players which are exclusively used for playback.
In digital recording equipment such as DVD recorders, recording is generally performed according to the DVD-VR standard because editing is easy. However, to perform playback by other equipment such as a DVD player, it is necessary to convert the format of a content recorded according to the DVD-VR standard into another format conforming to the DVD-video standard.
To convert the format of a recorded content from the DVD-VR standard into the DVD-video standard, a method in which a digital signal is decoded, coded again and then recorded can be used. In this method, however, coding is performed again after decoding. Accordingly, this method has not only a problem in which the time necessary for the conversion is equal to the actual length of the content but also a problem in which the image quality of the content deteriorates.
In view of this, a technique of converting a digital-recorded content into another format while leaving the content digital without decoding is proposed. For example, an apparatus and a method for converting a bit stream in an RTR (Real Time Recording) format into a bit stream in a DVD-video standard format are disclosed in Patent Document 1. Hereinafter, a conversion in which a bit stream conforming to the DVD-VR standard as data in the RTR format is directly converted into a bit stream conforming to the DVD-video standard while leaving the bit stream digital without decoding will be referred to as a “digital conversion”.    Patent Document 1: Japanese Unexamined Patent Publication No. 2003-242721